/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id$
 */
package wx.xml.xalan.xpath.compiler;

/**
 * Operations codes for XPath.
 * <p>
 * Code for the descriptions of the operations codes:
 * [UPPER CASE] indicates a literal value,
 * [lower case] is a description of a value,
 * ([length] always indicates the length of the operation,
 * including the operations code and the length integer.)
 * {UPPER CASE} indicates the given production,
 * {description} is the description of a new production,
 * (For instance, {boolean expression} means some expression
 * that should be resolved to a boolean.)
 * * means that it occurs zero or more times,
 * + means that it occurs one or more times,
 * ? means that it is optional.
 * <p>
 * returns: indicates what the production should return.
 */
public class OpCodes {

    /**
     * [ENDOP]
     * Some operators may like to have a terminator.
     *
     * @xsl.usage advanced
     */
    public static final int ENDOP = -1;

    /**
     * [EMPTY]
     * Empty slot to indicate NULL.
     */
    public static final int EMPTY = -2;

    /**
     * [ELEMWILDCARD]
     * Means ELEMWILDCARD ("*"), used instead
     * of string index in some places.
     *
     * @xsl.usage advanced
     */
    public static final int ELEMWILDCARD = -3;

    /**
     * [OP_XPATH]
     * [length]
     * {expression}
     * <p>
     * returns:
     * XNodeSet
     * XNumber
     * XString
     * XBoolean
     * XRTree
     * XObject
     *
     * @xsl.usage advanced
     */
    public static final int OP_XPATH = 1;

    /**
     * [OP_OR]
     * [length]
     * {boolean expression}
     * {boolean expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_OR = 2;

    /**
     * [OP_AND]
     * [length]
     * {boolean expression}
     * {boolean expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_AND = 3;

    /**
     * [OP_NOTEQUALS]
     * [length]
     * {expression}
     * {expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_NOTEQUALS = 4;

    /**
     * [OP_EQUALS]
     * [length]
     * {expression}
     * {expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_EQUALS = 5;

    /**
     * [OP_LTE] (less-than-or-equals)
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_LTE = 6;

    /**
     * [OP_LT] (less-than)
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_LT = 7;

    /**
     * [OP_GTE] (greater-than-or-equals)
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_GTE = 8;

    /**
     * [OP_GT] (greater-than)
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_GT = 9;

    /**
     * [OP_PLUS]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_PLUS = 10;

    /**
     * [OP_MINUS]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_MINUS = 11;

    /**
     * [OP_MULT]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_MULT = 12;

    /**
     * [OP_DIV]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_DIV = 13;

    /**
     * [OP_MOD]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_MOD = 14;

    /**
     * [OP_QUO]
     * [length]
     * {number expression}
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_QUO = 15;

    /**
     * [OP_NEG]
     * [length]
     * {number expression}
     * <p>
     * returns:
     * XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_NEG = 16;

    /**
     * [OP_STRING] (cast operation)
     * [length]
     * {expression}
     * <p>
     * returns:
     * XString
     *
     * @xsl.usage advanced
     */
    public static final int OP_STRING = 17;

    /**
     * [OP_BOOL] (cast operation)
     * [length]
     * {expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_BOOL = 18;

    /**
     * [OP_NUMBER] (cast operation)
     * [length]
     * {expression}
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int OP_NUMBER = 19;

    /**
     * [OP_UNION]
     * [length]
     * {PathExpr}+
     * <p>
     * returns:
     * XNodeSet
     *
     * @xsl.usage advanced
     */
    public static final int OP_UNION = 20;

    /**
     * [OP_LITERAL]
     * [3]
     * [index to token]
     * <p>
     * returns:
     * XString
     *
     * @xsl.usage advanced
     */
    public static final int OP_LITERAL = 21;
    /**
     * [OP_VARIABLE]
     * [4]
     * [index to namespace token, or EMPTY]
     * [index to function name token]
     * <p>
     * returns:
     * XString
     *
     * @xsl.usage advanced
     */
    public static final int OP_VARIABLE = 22;
    /**
     * [OP_GROUP]
     * [length]
     * {expression}
     * <p>
     * returns:
     * XNodeSet
     * XNumber
     * XString
     * XBoolean
     * XRTree
     * XObject
     *
     * @xsl.usage advanced
     */
    public static final int OP_GROUP = 23;
    /**
     * [OP_EXTFUNCTION] (Extension function.)
     * [length]
     * [index to namespace token]
     * [index to function name token]
     * {OP_ARGUMENT}
     * <p>
     * returns:
     * XNodeSet
     * XNumber
     * XString
     * XBoolean
     * XRTree
     * XObject
     *
     * @xsl.usage advanced
     */
    public static final int OP_EXTFUNCTION = 24;
    /**
     * [OP_FUNCTION]
     * [length]
     * [FUNC_name]
     * {OP_ARGUMENT}
     * [ENDOP]
     * <p>
     * returns:
     * XNodeSet
     * XNumber
     * XString
     * XBoolean
     * XRTree
     * XObject
     *
     * @xsl.usage advanced
     */
    public static final int OP_FUNCTION = 25;
    /**
     * [OP_ARGUMENT] (Function argument.)
     * [length]
     * {expression}
     * <p>
     * returns:
     * XNodeSet
     * XNumber
     * XString
     * XBoolean
     * XRTree
     * XObject
     *
     * @xsl.usage advanced
     */
    public static final int OP_ARGUMENT = 26;
    /**
     * [OP_NUMBERLIT] (Number literal.)
     * [3]
     * [index to token]
     * <p>
     * returns:
     * XString
     *
     * @xsl.usage advanced
     */
    public static final int OP_NUMBERLIT = 27;
    /**
     * [OP_LOCATIONPATH]
     * [length]
     * {FROM_stepType}
     * | {function}
     * {predicate}
     * [ENDOP]
     * <p>
     * (Note that element and attribute namespaces and
     * names can be wildcarded '*'.)
     * <p>
     * returns:
     * XNodeSet
     *
     * @xsl.usage advanced
     */
    public static final int OP_LOCATIONPATH = 28;
    /**
     * [OP_PREDICATE]
     * [length]
     * {expression}
     * [ENDOP] (For safety)
     * <p>
     * returns:
     * XBoolean or XNumber
     *
     * @xsl.usage advanced
     */
    public static final int OP_PREDICATE = 29;
    /**
     * [OP_MATCHPATTERN]
     * [length]
     * {PathExpr}+
     * <p>
     * returns:
     * XNodeSet
     *
     * @xsl.usage advanced
     */
    public static final int OP_MATCHPATTERN = 30;

    // public static final int LOCATIONPATHEX_MASK = 0x0000FFFF;
    // public static final int LOCATIONPATHEX_ISSIMPLE = 0x00010000;
    // public static final int OP_LOCATIONPATH_EX = (28 | 0x00010000);
    /**
     * [OP_LOCATIONPATHPATTERN]
     * [length]
     * {FROM_stepType}
     * | {function}{predicate}
     * [ENDOP]
     * returns:
     * XNodeSet
     *
     * @xsl.usage advanced
     */
    public static final int OP_LOCATIONPATHPATTERN = 31;
    /**
     * [NODETYPE_COMMENT]
     * No size or arguments.
     * Note: must not overlap function OP number!
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_COMMENT = 1030;
    /**
     * [NODETYPE_TEXT]
     * No size or arguments.
     * Note: must not overlap function OP number!
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_TEXT = 1031;
    /**
     * [NODETYPE_PI]
     * [index to token]
     * Note: must not overlap function OP number!
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_PI = 1032;
    /**
     * [NODETYPE_NODE]
     * No size or arguments.
     * Note: must not overlap function OP number!
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_NODE = 1033;
    /**
     * [NODENAME]
     * [index to ns token or EMPTY]
     * [index to name token]
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODENAME = 34;
    /**
     * [NODETYPE_ROOT]
     * No size or arguments.
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_ROOT = 35;
    /**
     * [NODETYPE_ANY]
     * No size or arguments.
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_ANYELEMENT = 36;
    /**
     * [NODETYPE_ANY]
     * No size or arguments.
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int NODETYPE_FUNCTEST = 1034;
    /**
     * [FROM_stepType]
     * [length, including predicates]
     * [length of just the step, without the predicates]
     * {node test}
     * {predicates}?
     * <p>
     * returns:
     * XBoolean
     *
     * @xsl.usage advanced
     */
    public static final int AXES_START_TYPES = 37;
    /**
     * ancestor axes opcode.
     */
    public static final int FROM_ANCESTORS = 37;
    /**
     * ancestor-or-self axes opcode.
     */
    public static final int FROM_ANCESTORS_OR_SELF = 38;
    /**
     * attribute axes opcode.
     */
    public static final int FROM_ATTRIBUTES = 39;
    /**
     * children axes opcode.
     */
    public static final int FROM_CHILDREN = 40;
    /**
     * descendants axes opcode.
     */
    public static final int FROM_DESCENDANTS = 41;
    /**
     * descendants-of-self axes opcode.
     */
    public static final int FROM_DESCENDANTS_OR_SELF = 42;
    /**
     * following axes opcode.
     */
    public static final int FROM_FOLLOWING = 43;
    /**
     * following-siblings axes opcode.
     */
    public static final int FROM_FOLLOWING_SIBLINGS = 44;
    /**
     * parent axes opcode.
     */
    public static final int FROM_PARENT = 45;
    /**
     * preceding axes opcode.
     */
    public static final int FROM_PRECEDING = 46;
    /**
     * preceding-sibling axes opcode.
     */
    public static final int FROM_PRECEDING_SIBLINGS = 47;
    /**
     * self axes opcode.
     */
    public static final int FROM_SELF = 48;
    /**
     * namespace axes opcode.
     */
    public static final int FROM_NAMESPACE = 49;
    /**
     * '/' axes opcode.
     */
    public static final int FROM_ROOT = 50;
    /**
     * For match patterns.
     *
     * @xsl.usage advanced
     */
    public static final int MATCH_ATTRIBUTE = 51;
    /**
     * For match patterns.
     *
     * @xsl.usage advanced
     */
    public static final int MATCH_ANY_ANCESTOR = 52;
    /**
     * For match patterns.
     *
     * @xsl.usage advanced
     */
    public static final int MATCH_IMMEDIATE_ANCESTOR = 53;
    /**
     * The end of the axes types.
     */
    public static final int AXES_END_TYPES = 53;
    /**
     * The low opcode for nodesets, needed by getFirstPredicateOpPos and
     * getNextStepPos.
     */
    static final int FIRST_NODESET_OP = 22;
    /**
     * The last opcode for stuff that can be a nodeset.
     */
    static final int LAST_NODESET_OP = 25;
    /**
     * The next free ID.  Please keep this up to date.
     */
    private static final int NEXT_FREE_ID = 99;
}
